Heterocladiella Ignatov & Fedosov, 2019

Heterocladiella Ignatov & Fedosov View in CoL , gen. nov.

Type species: Heterocladiella dimorpha (Bridel) Ignatov & Fedosov , comb. nov. – Basionym: Hypnum dimorphum Brid., Muscol. Recent. , suppl. 2: 149. 1812.

Species included: Heterocladiella procurrens (Mitten) Ignatov & Fedosov , comb. nov. – Basionym: Pterogonium procurrens Mitt., J. Linn. Soc., Bot. 8: 37. 1864.

Description: Leaves spreading to erect-appressed when dry, erect-spreading when moist; stem leaves to 1 mm; margins serrate to serrulate; apex acute; costa usually double and short to just below mid leaf; laminal cells papillose, papillae single, in distal end of cell; basal cells smooth.

Differentiation: The morphological distinction between Heterocladiella and Heterocladium includes (1) branching pattern: more or less regularly unipinnate in Heterocladiella and strongly to moderately irregularly repeatedly branched in Heterocladium ; (2) always smooth stem cells in Heterocladiella vs. occasionally papillose in Heterocladium ; (3) laminal cells smooth to multipapillose on dorsal surface in Heterocladium vs. smooth to unipapillose on dorsal surface in Heterocladiella ; (4) leaves appressed at their bases and then reflexed to squarrose in Heterocladiella vs. leaves somewhat spreading from stem at their bases in Heterocladium . Hedenäs & Bisang (2011) found that species of Heterocladiella have both large and dwarf males, whereas dwarf males in Heterocladium s. str. have not been observed.

* * * According to the Tropicos database (accessed 2 May 2019), there are nine species of the genus currently accepted. Two are referred here to Heterocladiella , and none of the other species accepted by Tropicos belong to this

On the taxonomy of Anomodontaceae and Heterocladium (Bryophyta) 97